Ultraviolet light absorbing composition

a technology of light absorption and composition, applied in the direction of synthetic resin layered products, transportation and packaging, chemistry apparatus and processes, etc., can solve problems such as unwanted effects

Inactive Publication Date: 2006-04-20
CRYOVAC ILLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0004] The present invention may address one or more of the aforementioned problems. In one embodiment, an ultraviolet light absorbing composition comprises first and second benzotriazoles having different UV absorption characteristics. The weight ratio of the first benzotriazole to the second benzotriazole is at least about 0.05:1 and at most about 20:1.

Problems solved by technology

In some applications, UV light absorbers may migrate or “bloom” to the surface of the product in which they are incorporated, which may cause unwanted effects.

Method used

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  • Ultraviolet light absorbing composition
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Examples

Experimental program
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examples

[0209] In the examples below, these abbreviations have the following meanings:

[0210] UVA1 is the UV absorber 2-[2-Hydroxy-3,5-di-(1,1-dimethylbenzyl)phenyl]-2H-benzotriazole available from Ciba Specialty Chemicals under the TINUVIN 234 trade name.

[0211] UVA2 is the UV absorber 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-2H-5-chlorobenzotriazole available from Ciba Specialty Chemicals under the TINUVIN 326 trade name.

[0212] Six thermoplastic films each having a thickness of 66 microns were made. Each film had the same composition except for the concentration and / or type of UV absorber, as set forth below in Table 1. The percent transmission of UV light through each film at the specified wavelength was measured and the results are also set forth in Table 1.

TABLE 1UVA1UVA2% UV Light Transmission(wt. %)(wt. %)@ 300 nm@350 nm@390 nmSample 100657076Sample 21.20122478Sample 301.2163672Example 10.60.682038Example 20.90.32414Example 30.30.92412

[0213] It was surprising and unexpected that for...

example 4

[0216] A nine-layer film having a 2.6 mil thickness and the following structure was made by coextrusion: [0217] 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9

[0218] where the number represents a film layer and the slash represents a film layer interface. Table 2 shows more detail about the film composition and structure.

TABLE 2Film LayerCompositionThickness (mils)197.5% LDPE; 2% MB; 0.5% UVA10.3299.5% LDPE; 0.5% UVA10.53100% LLDPE(mod)0.2480% PA-6; 19.5% PA-6, I / 6, T(mod);0.150.125% UVA1 0.375 UVA2;599% PA-6, I / 6, T(mod); 0.25% UVA1;0.30.75% UVA2680% PA-6; 19.5% PA-6, I / 6, T(mod);0.150.125% UVA1; 0.375 UVA27100% LLDPE(mod)0.2899.5% LDPE; 0.5% UVA10.5997.5% LDPE; 2% MB; 0.5% UVA10.3

LDPE is a low density polyethylene polymer.

MB is a masterbatch comprising antiblock agent.

LLDPE(mod) is an anhydride-modified linear low density polyethylene.

PA-6 is a nylon-6.

PA-6, I / 6, T(mod) is a modified amorphous nylon-6, I / 6, T available from EMS-Grivory under the Grivory FE 5746 development product number, believed to ha...

example 5

[0220] A film was made the same as the Example 4 film—except that layers 1, 2, 8, and 9 each had 0.375% UVA2 and 0.125% UVA1 rather than 0.5% UVA1. The resulting Example 5 film had good intra-film bond strength. The layers of the Example 5 film did not separate from each other after handling. The Example 5 film blocked at least about 80% of the transmission of UV light for wavelengths up to 400 nm.

[0221] After a day to allow for any “blooming” of the UV light absorber to the surface of the films, the Example 5 film was observed to have much better (i.e., lower) haze characteristics and better (i.e., higher) transparency characteristics than the Example 4 film and the Example 6 film (discussed below). This is believed to occur because the majority of the UV light absorbers, in the outer layers and next to outer layers, in the Example 5 film was UVA2, rather than UVA1 as in the Examples 4 and 6 films.

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Abstract

An ultraviolet light absorbing composition comprises first and second benzotriazoles having different UV absorption characteristics. The weight ratio of the first benzotriazole to the second benzotriazole is at least about 0.05:1 and at most about 20:1.

Description

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 835,792 filed Apr. 30, 2004 (Attorney Docket D43745-01), which is incorporated herein in its entirety by reference.BACKGROUND OF THE INVENTION [0002] The present invention relates to ultraviolet light absorbers, and more particularly to compositions combining different ultraviolet light absorbers. [0003] It may be desirable to incorporate ultraviolet (“UV”) light absorber into a product in order to reduce the negative effects, such as deterioration, that UV light may cause to the product. It may also be desirable to incorporate UV light absorber into a product in order to reduce the UV light transmission through the product. In some applications, UV light absorbers may migrate or “bloom” to the surface of the product in which they are incorporated, which may cause unwanted effects. Therefore, it may be desirable to minimize the amount of UV light absorber incorporated into a product, while still...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B32B27/34B32B27/08C08G69/48
CPCB32B27/34C08K5/3475C08K5/3492C08K2201/014Y10T428/31725Y10T428/31913
Inventor BEKELE, SOLOMON
Owner CRYOVAC ILLC
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